The present invention relates to a microbicide for detergents and to a denture detergent comprising the microbicide.
It is important to prevent microbial contamination by a detergent having microbicidal effect for keeping sanitary life environment, and therefore, microbicides useful for detergents are greatly necessitated. Such microbicides have been presently used in various detergents.
Microbicide is generally required to satisfy the conditions that it exhibits microbicidal effect extensively on various microorganisms in nature, that it is effective in a small amount, and that it is non-toxic, non-stimulative and safe to a living body. In the case that the microbicide is used in combination with a detergent, such as a microbicide for detergents, it would be further required that it is stable in a detergent formulation, that its microbicidal effect is not inhibited by pH and other ingredients, and that it does not spoil the function, color and flavor of the detergent, in addition to the requirements above described.
Microbicides are often used in a denture detergent, which is a sort of detergents, like in other detergents. Since it is difficult to completely remove the indigenous microbiota in mouth only by the action of the detergent, these indigenous microbiota are usually sterilized by the action of a microbicide contained in a denture detergent. One of the serious problems for users of dentures is xe2x80x9cpeculiar halitosisxe2x80x9d, and such halitosis is caused by proliferation of the indigenous microbiota in mouth. One of the indigenous microbiota in mouth, Candida albicans, is also a pathogen of denture stomatitis. Thus, in view of prevention of the halitosis and denture stomatitis, it is greatly important to use a microbicide in a denture detergent. Microbicides contained in commercially available denture detergents are active oxygen generating agents, such as peroxides, or enzymes, and denture cleaning is conducted by using one of them alone or in combination of two or more of them.
Although it has been studied for finding a microbicide that can exhibit higher microbicidal effect within shorter time compared to the above-mentioned conventional microbicides for denture detergents, practically usable microbicide has not yet been found. The main reason of said less usable microbicide is due to the inhibition of the microbicidal effect of the microbicide by the interaction with other ingredient(s) in a detergent. For example, in the case that sodium lauryl sulfate, which is preferably and widely used as a detergent ingredient in mouthwashes and denture detergents, is used as a detergent ingredient together with a cationic microbicide such as cetylpyridinium chloride and dequalinium chloride, they react with each other to form a white insoluble material, which results in inhibition of the microbicidal effect. In the case that sodium lauryl sulfate is used as a detergent ingredient together with a microbicidal ingredient such as sodium salicylate, phenyl salicylate, and the like, they would not cause inhibition of the microbicidal effect. However, when this combination is used in a denture cleaning, it will provide rather unpleasant feeling than refreshing feeling in the mouth of the denture user after the denture cleaning.
When a nonionic surfactant, such as Amisol MDE, Amisol LME, Emulgen 950 and Emulgen PP-290, is used as a detergent ingredient in combination with a microbicide such as cetylpyridinium chloride, which is inert to the surfactant, the detergent cannot exhibit sufficient detergent and effervescent effects contrary to a detergent containing sodium lauryl sulfate, and hence, it cannot achieve to desired detergent function.
It is an object of the present invention to provide a microbicide for detergents exhibiting excellent microbicidal effect within shorter time in comparison with conventional microbicides for detergents, without inhibition of the microbicidal effects by other ingredient in the detergent, and a denture detergent comprising said microbicide. It is another object of the present invention to provide a microbicide for detergents, which does not inhibit the action of a detergent comprising sodium lauryl sulfate having superior detergent and effervescent effects. It is yet another object of the present invention to provide a denture detergent, which has a superior microbicidal effect with keeping the excellent detergent and effervescent actions of sodium lauryl sulfate, and is comfortably used.
The present inventors have extensively studied to achieve the objects described above and found that an inorganic carrier conjugated with an antimicrobial metal ion, which may be hereinafter referred to as xe2x80x9cthe microbicide of the inventionxe2x80x9d, is extremely superior as a microbicide for detergents. Thus, the microbicide of the invention has superior microbicidal effect, and it exhibits the superior microbicidal effect within a short time since the microbicidal effect is not inhibited by other ingredients in the detergent.
Thus, the present invention provides a microbicide for detergents comprising an inorganic carrier conjugated with an antimicrobial metal ion. Furthermore, the present invention provides a denture detergent comprising an inorganic carrier conjugated with an antimicrobial metal ion.
Inorganic carriers conjugated with an antimicrobial metal ion have been hitherto mixed with materials such as synthetic resins, rubber materials, paints, synthetic fiber and papers for the purpose of enhancing the antimicrobial property of these materials. Such antimicrobial materials have been used in various fields, such as electric home appliances, house furnishings, office supplies, building materials, wrappings, medical supplies, and the like. However, the present inventors have first found that such inorganic carriers conjugated with an antimicrobial metal ion are effective for improving the microbicidal property of a detergent and exhibit their microbicidal effect on a subject to be cleaned.